MSP stops working when using 2 objects

Hello MaxMSP members,
I’m quite new to this forum but after some long search, I still didn’t find anything that has to do with the problem I’m having with MaxMSP.

When I make a cycle~ object, lets say "cycle~ 440" and connect it to an ezdac object, a tone starts playing. So far so good right? But when I create (not even connecting) another object, say, scope~, MSP just stops working. There’s no error in the max window, but it just doesn’t work until I restart Max. And when I do, it just works until I connect another object.
Does anyone of you guys know how to solve this?
Thanks in advance.